Threaded lens hood.

Lens hoods protect the lenses from bumps and the creation of flares from light sources that can ruin your image.

This particular hood is designed for SLR lenses with interchangeable zooms that have specific filter threads. It is optimized to provide coverage for wide or telephoto zoom lenses.

Lens hoods are primarily designed to prevent unwanted stray light from entering the lens, extending and shading the edge of the lens. Additionally, due to the extension of the lens edge, it provides extra protection from potential accidents.